1. Field of the Invention
The present invention is in the field of pulsation dampener devices.
2. The Prior Art
As conducive to an understanding of the invention, it is noted that where a hydraulic system or the like utilizes a reciprocating pump, such as a piston pump, pulses are generated. The frequency and amplitude of the pulses is dependent upon the number of pistons in the pump and its speed of operation.
Obviously, the pulses generated are transmitted through the system. If the amplitude of the pulses is sufficiently great, the transmitted shocks may induce damage in the various components of the system, such as the hydraulic lines, pipe fittings, valves, etc. Also, the uncontrolled pulses may cause leakage, breakage of lines and the like.
In order to reduce the shocks transmitted to the system, it is conventional to employ pulse dampener devices comprising, generally, a pressure vessel divided into two chambers of variable size by a bladder or like diaphragm. One of the chambers is charged with gas under pressure whereas the other chamber is in communication with the liquid, normally oil of the hydraulic system. As the liquid under pressure from the pump is forced into the oil chamber, the gas in the other chamber of the pressure vessel will be compressed, transferring energy to the gas and dampening the amplitude of the pulse. As examples of pulse dampeners of the type described, reference may be made to U.S. Pat. No. 3,782,418 of Jan. 1, 1974 and U.S. Pat. No. 3,857,413 of Dec. 31, 1974 in both of which a bypass path is provided for the passage of oil to reduce turbulence and hence reduce the pressure drop.
In the latter patent, manual control means are provided for increasing or decreasing the cross-sectional flow area of the by-pass path within the pulsation dampener device for the passage of oil in order to tune said turbulance reduction means based on the desired output characteristics of the system.
However, where the turbulance is reduced by increasing the flow area as set forth in U.S. Pat. No. 3,857,413, such adjustment may be effected only to provide correction to an average series of flow parameters. Thus, while the turbulence effect may be corrected based on a given pressure in the conduit upstream of the device and a given setting of the control means, it may be totally inappropriate if the pressure upstream of the device should drop below a predetermined amount.